Solid-state relay

Abstract

The utility model relates to a solid-state relay, which comprises a switch control circuit, a transformer control circuit, a transformer, a rectification drive circuit and a switch circuit which are sequentially connected in series, the switching circuit comprises a switching tube Q3 and a switching tube Q4 which are connected in series reversely, grid electrodes of the switching tube Q3 and the switching tube Q4 are jointly connected with a driving control signal output by the rectification driving circuit, source electrodes of the switching tube Q3 and the switching tube Q4 are connected with an output signal of the rectification driving circuit, and drain electrodes of the switching tube Q3 and the switching tube Q4 output an output signal; or the drain electrodes of the switch tube Q3 and the switch tube Q4 are connected with the output signal of the rectification driving circuit, and the source electrodes of the switch tube Q3 and the switch tube Q4 output the output signal. According to the solid-state relay, the mos tubes or the IGBTs which are reversely connected in series serve as switching devices, meanwhile, the high-frequency on-board transformer is adopted for coupling, the switching speed of the solid-state relay is higher, the driving power is smaller, meanwhile, extra isolation power sources and driving signals are reduced, the number of used devices is reduced, the product size is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of relays, and more specifically, to a solid-state relay. Background Art

[0002] A solid-state relay is a contactless electronic switch with an isolation function. It uses semiconductor devices to realize the control and switching functions of electrical signals, replacing the mechanical contacts of traditional relays. Existing solid-state relays usually use thyristors as switching devices. Due to the inherent uncontrollable shutdown characteristics of thyristors, they are usually used to control the on and off of alternating current, and cannot be used to control the on and off of direct current. At the same time, thyristors are current-controlled devices, which require strong current triggering to turn on. The power required for the control signal is relatively large, resulting in a complex control circuit, large size, and high cost. In addition, the thyristor conduction voltage drop is large, resulting in large relay opening losses and energy waste. Utility Model Content

[0003] The technical problem to be solved by the utility model is to propose a solid-state relay in view of the above-mentioned defects of the prior art.

[0004] The technical solution adopted by the utility model to solve the technical problem is: a solid-state relay is proposed, comprising: a switch control circuit, a transformer control circuit, a transformer, a rectifier drive circuit and a switch circuit connected in series in sequence;

[0005] The switch circuit comprises: a switch tube Q3 and a switch tube Q4 connected in anti-series, the gates of the switch tubes Q3 and Q4 are commonly connected to a driving control signal output by a rectifier drive circuit, the sources of the switch tubes Q3 and Q4 are connected to the output signal of the rectifier drive circuit, and the drains of the switch tubes Q3 and Q4 output the output signal; or the drains of the switch tubes Q3 and Q4 are connected to the output signal of the rectifier drive circuit, and the sources of the switch tubes Q3 and Q4 output the output signal;

[0006] The switch tube Q3 and the switch tube Q4 are NMOS tubes or IGBTs of the same model;

[0007] The transformer is an on-board transformer, which is composed of two groups of multi-turn coils coupled to each other designed on a PCB board;

[0008] The primary side of the transformer is driven by a capacitor three-point oscillation circuit, and the secondary side of the transformer is driven by a voltage-doubling rectifier filter circuit.

[0009] According to some embodiments of the present utility model, resistor R4 and transistor Q2, the first end of resistor R4 is connected to the enable signal EN, the second end of resistor R4 is connected to the base of transistor Q2, the emitter of transistor Q2 is grounded, and the collector of transistor Q2 is connected to the input end of the transformer control circuit.

[0010] According to some embodiments of the present invention, the further device further comprises: a control pin, and the enable signal EN is sent by the control pin.

[0011] According to some embodiments of the present utility model, the transformer control circuit includes: a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3, a transistor Q1 and a primary coil of a transformer T1;

[0012] The first end of the resistor R1 is connected to the power supply voltage VCC, the second end of the resistor R1 is connected to the first end of the resistor R2 and the base of the transistor Q1, the second end of the resistor R2 is connected to the second end of the resistor R3 and the collector of the transistor Q2, the capacitor C3 is connected in parallel to the two ends of the resistor R2, the first end of the resistor R3 is connected to the emitter of the transistor Q1, the second end of the capacitor C1 and the first end of the capacitor C2, the first end of the capacitor C1 is connected to the first end of the resistor R1 and the first end of the primary coil, and the second end of the capacitor C2 is connected to the collector of the transistor Q1 and the second end of the primary coil.

[0013] According to some embodiments of the utility model, the rectifier driving circuit includes: a diode D1, a diode D2, a capacitor C4, a capacitor C5, a resistor R5, and a resistor R6;

[0014] The first end of the secondary coil of the transformer T1 is connected to the anode of the diode D1 and the cathode of the diode D2, the cathode of the diode D1 is connected to the first end of the capacitor C4, the first end of the resistor R5 and the first end of the resistor R6, the second end of the capacitor C4 is connected to the second end of the secondary coil of the transformer T1 and the first end of the capacitor C5, the second end of the capacitor C5 is connected to the anode of the diode D2, the second end of the resistor R5 and the source or drain of the switch tube Q3, the switch tube Q4, and the second end of the resistor R6 is connected to the gate of the switch tube Q3, the switch tube Q4.

[0015] The implementation of the solid-state relay of the utility model has the following beneficial effects: by using anti-series MOS tubes or IGBT tubes as switching devices and adopting high-frequency on-board transformer coupling, the switching speed of the solid-state relay is faster and the driving power is smaller. At the same time, the additional isolated power supply and driving signal are reduced, the number of devices used is reduced, the product volume is reduced, and the production cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is the principle diagram of the solid-state relay of the utility model;

[0018] Figure 2 It is a circuit diagram of the solid-state relay of the utility model. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] See also Figure 1 and Figure 2 The embodiment of the utility model provides a solid-state relay, comprising: a switch control circuit 1, a transformer control circuit 2, a transformer, a rectifier drive circuit 3 and a switch circuit 4 connected in series in sequence, the switch circuit 4 comprises: a switch tube Q3 and a switch tube Q4 connected in anti-series, the gates of the switch tubes Q3 and Q4 are commonly connected to the drive control signal output by the rectifier drive circuit 3, the source of the switch tubes Q3 and Q4 are connected to the output signal of the rectifier drive circuit 3, and the drain of the switch tubes Q3 and Q4 outputs the output signal; or the drain of the switch tubes Q3 and Q4 is connected to the output signal of the rectifier drive circuit 3, and the source of the switch tubes Q3 and Q4 outputs the output signal. When the drive control signal output by the rectifier drive circuit 3 is at a high level, the switch tubes Q3 and Q4 are turned on at the same time, and when the drive control signal is at a low level, the switch tubes Q3 and Q4 are turned off at the same time. The switch tubes Q3 and Q4 are NMOS tubes or IGBTs (insulated gate bipolar transistors) of the same model. NMOS tubes and IGBTs are voltage-driven devices with the characteristics of small on-state voltage drop and small driving power. They have faster switching speeds and smaller driving power, and can reliably control the on and off of AC or DC power at high speed.

[0021] The switch control circuit 1 includes: a resistor R4 and a transistor Q2, a first end of the resistor R4 is connected to an enable signal EN, a second end of the resistor R4 is connected to the base of the transistor Q2, an emitter of the transistor Q2 is grounded, and a collector of the transistor Q2 is connected to the input end of the transformer control circuit 2. The transistor Q2 is an NPN transistor, and when the enable signal EN is higher than 0.7V, the transistor Q2 can be turned on.

[0022] It should be noted that the solid-state relay of the present invention provides an independent control pin, and the control pin sends an enable signal EN to facilitate practical application.

[0023] The transformer control circuit 2 includes: a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3, a transistor Q1 and a primary coil of a transformer T1, a first end of the resistor R1 is connected to a power supply voltage VCC, a second end of the resistor R1 is connected to a first end of the resistor R2 and a base of the transistor Q1, a second end of the resistor R2 is connected to a second end of the resistor R3 and a collector of the transistor Q2, a capacitor C3 is connected in parallel to two ends of the resistor R2, a first end of the resistor R3 is connected to an emitter of the transistor Q1, a second end of the capacitor C1 and a first end of the capacitor C2, a first end of the capacitor C1 is connected to a first end of the resistor R1 and a first end of the primary coil, and a second end of the capacitor C2 is connected to a collector of the transistor Q1 and a second end of the primary coil. The three segments of the capacitors C2 and C3 are respectively connected to the three poles of the transistor Q1, so that the transformer control circuit 2 constitutes a capacitor three-point high-frequency oscillation circuit, providing a driving control signal for a switch circuit 4 of a solid-state relay.

[0024] Transformer T1 is an on-board transformer, which is composed of two sets of multi-turn mutually coupled coils designed on the PCB board. By using the on-board transformer as the energy source and signal transmission channel of the drive control signal of the switch circuit 4, there is no need to provide additional isolated power supply and isolated drive signal, so that the solid-state relay becomes lighter as a whole, maintains good process consistency, and reduces costs.

[0025] The rectifier drive circuit 3 includes: a diode D1, a diode D2, a capacitor C4, a capacitor C5, a resistor R5, and a resistor R6. The first end of the secondary coil of the transformer T1 is connected to the anode of the diode D1 and the cathode of the diode D2. The cathode of the diode D1 is connected to the first end of the capacitor C4, the first end of the resistor R5, and the first end of the resistor R6. The second end of the capacitor C4 is connected to the second end of the secondary coil of the transformer T1 and the first end of the capacitor C5. The second end of the capacitor C5 is connected to the anode of the diode D2, the second end of the resistor R5, and the source or drain of the switch tube Q3 and the switch tube Q4. The second end of the resistor R6 is connected to the gate of the switch tube Q3 and the switch tube Q4. Among them, the diode D1, the diode D2, the capacitor C4, and the capacitor C5 constitute a voltage doubling rectifier circuit, which can reduce the number of turns of the secondary coil of the transformer T1 and facilitate the miniaturization of the transformer. When the transformer control circuit 2 oscillates, the secondary voltage of the transformer passes through the rectification filter of diode D1, diode D2, capacitor C4 and capacitor C5, providing a high-level driving control signal for the subsequent switch circuit 4, and the switch tube is turned on; when the transformer does not oscillate, there is no voltage on the secondary side of the transformer T1, and the charge on capacitors C4 and C5 is discharged through resistor R5. When the voltage on capacitors C4 and C5 is less than the gate conduction threshold of switch tubes Q3 and Q4, the switch tube is turned off. Resistor R6 is the gate resistor of the switch tube, which can be selected or short-circuited according to the actual application.

[0026] The primary side of the transformer T1 is driven by a capacitor three-point oscillation circuit, and the secondary side is rectified and filtered by a voltage-doubler rectifier circuit, so that the solid-state relay is controlled with fewer devices, thereby reducing the production cost of the solid-state relay.

[0027] The implementation of the solid-state relay of the utility model has the following beneficial effects: by using anti-series MOS tubes or IGBT tubes as switching devices and adopting high-frequency on-board transformer coupling, the switching speed of the solid-state relay is faster and the driving power is smaller. At the same time, the additional isolated power supply and driving signal are reduced, the number of devices used is reduced, the product volume is reduced, and the production cost is reduced.

[0028] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0029] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot limit the protection scope of the utility model. All equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.

[0030] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

Claims

1. A solid-state relay, characterized in that: include: A switch control circuit, a transformer control circuit, a transformer, a rectifier drive circuit and a switch circuit connected in series in sequence; The switch circuit comprises: a switch tube Q3 and a switch tube Q4 connected in anti-series, the gates of the switch tubes Q3 and Q4 are commonly connected to a driving control signal output by a rectifier drive circuit, the sources of the switch tubes Q3 and Q4 are connected to the output signal of the rectifier drive circuit, and the drains of the switch tubes Q3 and Q4 output the output signal; or the drains of the switch tubes Q3 and Q4 are connected to the output signal of the rectifier drive circuit, and the sources of the switch tubes Q3 and Q4 output the output signal; The switch tube Q3 and the switch tube Q4 are NMOS tubes or IGBTs of the same model; The transformer is an on-board transformer, which is composed of two groups of multi-turn coils coupled to each other designed on a PCB board; The primary side of the transformer is driven by a capacitor three-point oscillation circuit, and the secondary side of the transformer is driven by a voltage-doubling rectifier filter circuit.

2. The solid-state relay according to claim 1, characterized in that: Resistor R4 and transistor Q2, the first end of resistor R4 is connected to the enable signal EN, the second end of resistor R4 is connected to the base of transistor Q2, the emitter of transistor Q2 is grounded, and the collector of transistor Q2 is connected to the input end of the transformer control circuit.

3. The solid-state relay according to claim 2, characterized in that: Also includes: A control pin, wherein the enable signal EN is sent out by the control pin.

4. The solid-state relay according to claim 2, characterized in that: The transformer control circuit includes: a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3, a transistor Q1 and a primary coil of a transformer T1; The first end of the resistor R1 is connected to the power supply voltage VCC, the second end of the resistor R1 is connected to the first end of the resistor R2 and the base of the transistor Q1, the second end of the resistor R2 is connected to the second end of the resistor R3 and the collector of the transistor Q2, the capacitor C3 is connected in parallel to the two ends of the resistor R2, the first end of the resistor R3 is connected to the emitter of the transistor Q1, the second end of the capacitor C1 and the first end of the capacitor C2, the first end of the capacitor C1 is connected to the first end of the resistor R1 and the first end of the primary coil, and the second end of the capacitor C2 is connected to the collector of the transistor Q1 and the second end of the primary coil.

5. The solid-state relay according to claim 4, characterized in that: The rectifier driving circuit includes: a diode D1, a diode D2, a capacitor C4, a capacitor C5, a resistor R5, and a resistor R6; The first end of the secondary coil of the transformer T1 is connected to the anode of the diode D1 and the cathode of the diode D2, the cathode of the diode D1 is connected to the first end of the capacitor C4, the first end of the resistor R5 and the first end of the resistor R6, the second end of the capacitor C4 is connected to the second end of the secondary coil of the transformer T1 and the first end of the capacitor C5, the second end of the capacitor C5 is connected to the anode of the diode D2, the second end of the resistor R5 and the source or drain of the switch tube Q3, the switch tube Q4, and the second end of the resistor R6 is connected to the gate of the switch tube Q3, the switch tube Q4.

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